[meteorite-list] Are Mars Meteorites Magnetic?

[Pict]

On 07/01/2012 11:36, "Göran Axelsson" <axelsson at acc.umu.se> wrote:
<snip>
>For example an achondrite can have a very high permeability for water
>and a low magnetic permeability. In other words, an achondrite can be
>very porous and allow water to seep through it and not showing any
>ferromagnetism.

A rock can also be very porous (lots of spaces in the rock) and have
little permeability to fluids. There is not necessarily a direct
correlation. The permeability for any given fluid (e.g. water, oil, gas)
is dependent on the degree of communication between pore spaces, which is
contingent on the size and amount of physical pathways between pore
spaces. More connecting apertures between pore space results in greater
fluid permeability, but smaller apertures and pore spaces result in poorer
fluid permeability because of capillary pressure. In addition, In the case
of claystones (aka mudstones), there is generally a layer of bound water
sticking to the tiny clay particles that is immobile, reducing the total
porosity to an 'effective porosity'. Limestones can be very porous but
have poor fluid permeability due to the holes or 'vugs' in the rock being
largely interconnected.

I would presume extra-terrestrial lithologies can exhibit the same sorts
of variety in how their porosity or lack of it is organised.

Anyway, I was wondering that if magnetic permeability and fluid
permeability are at all analogous, if a corollary then exists. Is there
such a thing as magnetic porosity?

Does the disposition and particle size of any given magnetic substance
within a meteorite affect how strongly it is attracted to a magnet, as
well as the overall content of such material?

John